body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
    sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

code {
  font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New",
    monospace;
}

ul,
li,
p,
h1,
h2,
h3,
h4 {
  margin: 0;
  padding: 0;
}

ul,
li {
  list-style: none;
}

/* 清除浮动 */
.clearfix::after {
  visibility: hidden;
  display: block;
  font-size: 0;
  content: "";
  clear: both;
  height: 0;
}

.none {
  display: none;
}
